A conventional angular velocity sensor will be described with reference to a drawing. FIG. 14 is a perspective view of a detection element used for a conventional angular velocity sensor. Detection element 1 has a pair of fixed parts 16, horizontal beam 3, four arms 4, 5, 6 and 7, and weights 8, 17, 10 and 11. Horizontal beam 3 is connected between fixed parts 16. Arms 4, 5, 6 and 7 are connected at respective one ends thereof to horizontal beam 3. Weights 8, 17, and 11 are formed on the other ends of arms 4, 5, 6 and 7, respectively. Also, drive part 12 is formed on arm 4, monitor part 13 is formed on arm 5, and detection parts 14 and 15 are respectively formed on arms 6 and 7.
In this configuration, when an AC voltage is applied to drive part 12, arm 4 vibrates in an X-axis direction. Resonating with this vibration, arms 5, 6 and 7 also vibrate in the X-axis direction. Monitor part 13 detects a displacement of arm 5 in the X-axis direction. Detection parts 14 and 15 respectively detect displacements of arms 6 and 7 in a Y-axis direction caused by a Coriolis force generated when an angular velocity is applied to detection element 1. Detection element 1 detects an angular velocity around a Z-axis based on outputs of detection parts 14 and 15 (See, for example, PTL 1).